Kinetic study of pilot-scale supercritical CO2 extraction of rosemary (Rosmarinus officinalis) leaves

NOTICE: This is the author’s version of a work that was accepted for publication in Journal of Supercritical Fluids. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Supercritical Fluids, 55 (2011). http://dx.doi.org/10.1016/j.supflu.2010.09.030Rosmarinus officinalis (rosemary) extracts were obtained in a supercritical pilot-scale plant. Based on experimental information available in the literature for analytical or low-scale processes, extraction temperature and pressure were selected to be 313 K and 30 MPa. At these extraction conditions, the kinetic behavior of the pilot-scale overall extraction curve were determined with respect to yield, antioxidant activity and carnosic acid content. The overall extraction curve was represented using Sovova’s model; the average deviation between measured and calculated yields was lower than 2%. Mass transfer coefficients in the fluid and solid phases were determined and were compared with previous data reported in the literature for low-scale rosemary supercritical extraction. A two-stage depressurization procedure was accomplished and the effect of both on-line fractionation and extraction time on the antioxidant activity of the samples collected was studied. The antioxidant activity of the different fractions could be straight correlated with the carnosic acid content with a regression coefficient of 0.92This work has been financed by Universidad Autónoma de Madrid and Comunidad Autónoma de Madrid (ALIBIRD-S2009/AGR-1469) and project FUN-C-FOOD, CSD2007-00063 (CONSOLIDER-INGENIO) from Ministerio de Ciencia e Innovación, Spain

Supercritical CO2 extraction of Tetraclinis articulata: chemical composition, antioxidant activity and mathematical modeling

Operating conditions for extraction from the leaves of Tetraclinis articulata using supercritical carbon diox-ide (SCCO2) were studied to focus on the feasibility of obtaining volatile and nonvolatile fractions throughthe use of different extraction pressures (90, 280 and 1000 bar). In addition, influence of temperature,static pretreatment and dynamic extraction durations, particle size and CO2flow rate were investigated.All extracts were analyzed by GC–FID/MS and their antioxidant activity was measured using ABTS•+andDPPH•methods. Conventional hydrodistillation (HD) was also performed for comparison. At high CO2pressure (280 and 1000 bar), the amount of phenolics in the extracts was higher (respectively 102.03and 267.90 GAE mg/g) than for HD and supercritical fluid extraction (SFE) at 90 bar (respectively 8.89 and9.70 GAE mg/g). Correlatively, high antioxidant activity was found for high pressure SFE. Surprisingly, forextracts obtained by SFE at 90 bar, despite very low phenolic content, significant antioxidant activity wasobserved, while essential oil obtained by HD, which presented also low phenolic content, exhibited lowantioxidant activity.Physical aspects were only investigated for the low pressure supercritical extraction (90 bar) process.Qualitative assessment of kinetic curves together with their modeling revealed that the extraction pro-cess was mainly limited by the thermodynamic equilibrium of easily accessible solutes but where axialdispersion was significant. From this result a simple extrapolation procedure was proposed

Supercritical multicomponent solvent coal extraction

The yield of organic extract from the supercritical extraction of coal with larger diameter organic solvents such as toluene is increased by use of a minor amount of from 0.1 to 10% by weight of a second solvent such as methanol having a molecular diameter significantly smaller than the average pore diameter of the coal

Determination of Optimum Conditions for the Extraction of Squalene from Olive Pomace with Supercritical CO2

Olive pomace is a standard by-product of olive oil production containing valuable compounds recoverable by supercritical fluid extraction (SFE). The solvent/solubility characteristics of a supercritical fluid may be fine tuned by changing the external pressure-temperature conditions of the extraction. This allows for the selective extraction of certain compounds. The present study describes a series of experiments, the methodology, instrumentation, and results of supercritical extraction of olive pomace with CO2. The effects that primarily affect supercritical extraction, temperature, pressure and flow rate, have been investigated and monitored on, both, the concentration of squalene at the extract and the overall recovery of squalene from pomace. The Box-Behnken approach was used for designing the experiments. The effects are easily visualized in the resulting 3D plots, which were used for identifying the optimum extraction conditions

Extraction of raw plant material using supercritical carbon dioxide

Many of the herbs and spices used by humans are important medicinal compounds. The aim of this work is to investigate the extraction mechanisms of plant materials by using supercritical fluid extraction (SFE). In order to do this, a supercritical extraction system was designed and set-up allowing to use supercritical CO2 for the extraction of raw plant material, such as Sassafras albidum and Berberis vulgaris. The planned work found difficulties due to legal problems and the objective plant material had to be changed for this reason. The first plant considered was Sassafras albidum which later on was changed to Berberis vulgaris. Supercritical extraction in dynamic and steady state were executed in order to study the extraction parameters and attempt to recover a compound called berberine. The results of the experiments show that supercritical fluid extraction is a sufficient extraction method for the plant Berberis vulgaris. On the other hand, it was not possible to apply any analytical methods to prove that berberine was obtained since the amount of extract was not sufficient for the techniques available. Even so, physical properties such as smell and yellow color of the extract suggested that berberine might have been extracted. The whole designed supercritical extraction process needs improvements such as the introduction of organic solvents to increase the extraction yield and the introduction of an alternative analytical protocol such as High Performance Liquid Chromatography (HPLC)

Extraction of sweet wormwood (Artemisia annua L.) by supercritical carbon dioxide

In this study, supercritical carbon dioxide was applied for the extraction of Artemisia annua L. Moreover, the impact of different parameters of supercritical extraction on total yield was investigated and the obtained yields were compared to the ones obtained by conventional procedures, hydrodistillation and Soxhlet extraction. Supercritical fluid extraction at 40 °C and different pressures (100, 200, and 300 bar) resulted in extraction yields that were in the 2.23-5.18 % range, while the yields at 60 °C and the same pressures were in the range 2.43-3.35 %. The yields obtained by the Soxhlet extraction and hydrodistillation were 10.28 % and 0.10 %, respectively. Although supercritical fluid extraction is inferior to Soxhlet extraction in terms of the recovery of lipophilic components of A. annua, the Soxhlet extraction is not the method of choice for obtaining sweet wormwood extracts due to its numerous disadvantages that include the use of toxic solvents, extended extraction time, health safety of the product, the need for further processing, the impossibility of adjusting the selectivity and thus the composition of the product

Studies on the use of supercritical ammonia for ceramic nitride synthesis and fabrication

The extractability of ammonia halides (including ammonium thiocyanate) formed as byproducts from the synthesis of Si(NH)2 via ammonolysis of the corresponding silicon tetrahalides using supercritical NH3 as the extraction medium was investigated. It was found that the NH4SCN byproduct of ammonolysis of Si(SCN)4 can be almost completely extracted from the insoluble Si(NH)2 forming a promising system for the synthesis of pure Si(NH)2, one of the best precursors for Si3N4. In addition it was found that Si3N4, AlN, BN, and Si(NH)2 are insoluble in SC ammonia. Also discussed are design considerations for a supercritical ammonia extraction unit

Supercritical Carbon Dioxide Extraction Of Cyclosporine From The Fungus Beauvaria Nivea

Cyclosporine, or Cyclosporin A is an important new immunosuppressant drug, now used to prevent the immune rejection of a variety of organ transplants. Cyclosporine is produced by the fungus Beauvaria nivea ATCC 34921, also called Tolypocladium inflatum NRRL 8004. The current commercial Cyclosporine extraction process uses liquid organic solvents, with the risk of possibly hazardous residues in the final product. Governments are now aggressively regulating exposure to organic solvents. In view of this, a supercritical CO{dollar}\sb2{dollar} extraction process, which results in no organic solvent residues, is very good alternative.;Cyclosporine solubility in supercritical CO{dollar}\sb2{dollar} was studied using a newly designed apparatus to determine the feasibility of the extraction process. Cyclosporine solubilities up to 16-20 mg/mL of supercritical CO{dollar}\sb2{dollar} could be attained easily. The pressures and temperatures used ranged from 8.2 MPa to 34.0 MPa and 308.5 K to 343 K respectively. Cyclosporine mole fraction was found to correlate linearly with reduced densities above 1.5. When a methanol co-solvent was added Cyclosporine solubility in supercritical CO{dollar}\sb2{dollar} increased up to 20 times.;Cyclosporine extractions from the mycelia of the fungus Beauvaria nivea were done with supercritical CO{dollar}\sb2{dollar} at 32.0 MPa and 314 K. The highest extraction yields, with 70 to 80% of the original Cyclosporine present in the mycelia removed, were achieved using mycelia containing 7.2 to 29.5% moisture. Completely dried mycelia had lower extraction yields. The addition of methanol showed no effect on the Cyclosporine extraction yields. Co-extracted materials observed during the extraction experiments were tentatively identified as lipids. Scanning electron micrographs were taken of the mycelial structure and used to visualize the physical barriers to Cyclosporine removal.;The supercritical CO{dollar}\sb2{dollar} extraction process was found to be feasible for Cyclosporine removal from mycelia. This work contains the first report of its kind in the literature on the supercritical CO{dollar}\sb2{dollar} extraction of Cyclosporine from the mycelia of Beauvaria nivea, and the first data showing Cyclosporine solubility in supercritical CO{dollar}\sb2{dollar}. Further work remains to be done to optimize the yields and rates of supercritical CO{dollar}\sb2{dollar} extraction of Cyclosporine from mycelia

Extraction of alkylresorcinols from wheat bran with supercritical CO2

The supercritical fluid extraction (SFE) of wheat bran alkylresorcinols has been studied. Extractions were carried out at 40.0 MPa. The effect of particle size, static extraction pretreatment with supercritical CO2 (SC-CO2) and extraction temperature on the extraction kinetics was investigated. The extraction yield increased as the particle size decreased and with temperature. Extraction curves present a faster and linear initial extraction period followed by a slower extraction period. Based on these results the approximate mathematical model of Sovová was successfully applied to describe the extraction curves. The total content of alkylresorcinols was determined and compared with the alkylresorcinol content obtained by conventional organic solvent extraction. Due to the amphiphilic nature of these resorcinolic lipids, the extraction yield was higher for polar organic solvents than for SC-CO2. Characterization of supercritical extracts was also performed by determining the fatty acid composition and antioxidant activity.GALANG project (Ref.: ITC-20113029) financed by the Spanish Government through CDT

Optimizing the process of supercritical extraction of lemon balm (Melissa Officinalis L.)

This work investigates the process of extraction of lemon balm (Melissa officinalis L.) by treatment with carbon dioxide at supercritical conditions. The process kinetics is studied at different operational conditions, and the influence of some important regime parameters (pressure, temperature particle size, solvent flow-rate) on the extraction yield is experimentally determined. Besides the information for process intensity at particular operational regimes, the results are useful for selection of favourable operational conditions for better extraction, i.e. for production of larger quantity of extracted substances from unit mass of raw material